1. Field of the Invention
The present invention relates to a cutting machine to divide a CSP substrate of a rectangular shape provided with plural semiconductor chips, such as ICs and LSIs, formed thereon in a matrix fashion and covered with resin into individual semiconductor chips.
2. Related Art
A CSP substrate of this type, on which plural semiconductor chips, such as ICs and LSIs, are formed, is divided into individual semiconductor chips, for example, by a dividing machine known as a dicing machine. Each semiconductor chip is then packaged with resin in a chip size to be used widely by being incorporated into a circuit in electric devices, such as a mobile phone and a personal computer.
To divide a CSP substrate of this type, it is generally known to use a dicing machine for semiconductor wafers that enables cutting so precise that an error even in the order of some microns is not allowed. The dicing machine includes one chuck table and one cutting blade, and cuts a semiconductor wafer placed on the chuck table as follows. That is, cutting lines in the lengthwise direction and the crosswise direction that define semiconductor chips formed on the surface of the semiconductor wafer are detected to position the cutting blade by an alignment. The lengthwise and crosswise cutting positions along these streets are indexed precisely and stored, and on the basis of the cutting positions thus stored, for example, the cutting in the lengthwise direction is performed, after which the chuck table is rotated by 90° to perform the cutting in the crosswise direction next (see JP-A-2001-77057).
When a CSP substrate of this kind is divided, it does not have to be cut at a high degree of precision. However, the cutting is performed deliberately with an extremely high degree of precision as with the cutting of a semiconductor wafer that requires exact precision. This raises a problem that cutting efficiency is poor.
Such being the case, an object of the present invention is to solve the problems discussed above by providing a cutting machine capable of cutting a workpiece appropriately with a degree of precision as required at satisfactory efficiency when dividing a workpiece in the related art, that is, a plate-shaped material, such as a CSP substrate, that is not necessarily cut and divided exactly at a high degree of precision.